Research Excellence

Quantum information science is an emerging field, combining and drawing on the disciplines of physics, mathematics, computer science, and engineering, for the purpose of understanding how specific fundamental laws of quantum mechanics can be harnessed to improve the storage, transmission, and processing of data.

However, major challenges are found as quantum channels, the medium in which quantum information is transmitted, are vulnerable to disturbance from the external environment, which will lead to decoherence and inefficiency in the system during data transmission, where error occurs.

The study of Dr Sze Nung-sing, Raymond Associate Professor of the Department of Applied Mathematics, is to understand the mathematical framework of quantum error-correcting code for quantum systems by referencing Hilbert space theory, the theoretical basis of quantum mechanics that has been found a century ago, and to protect quantum information from errors due to decoherence and other quantum noise during transmission. 

Dr Sze's approach is to build mathematical techniques and tools so as to establish some new theoretical results or improve the existing frameworks, such as altering the way of physical transformations between sets of quantum states, and constructing simple encoding and decoding quantum circuits that increase the efficiency of data transmission in quantum channels.

Though claimed by Dr Sze that his study is still way far from commercialization and his work is mainly theory-based, his research indeed gives engineers the chance to understand different phenomena and build better quantum devices. The best practical case will be the building of quantum computers which run quantum algorithms that solve more complicated problems much more efficiently than conventional digital computers.

量子糾錯中的數學

量子資訊科學是一門新興的科目，當中結合了物理學、數學、電腦科學和工程學，藉此讓我們了解如何利用量子力學的特定基本定律，來提升數據儲存、傳送及處理的能力。

然而，作為一個傳遞量子資訊的媒介，量子通道很容易受到外在環境干擾，並因此會令系統在數據傳送過程中出現相位失調和效率欠佳的問題，繼而導致錯誤發生。這是目前研究這門學科所面對的難題之一。

這項由應用數學系副教授施能聖博士進行的研究，目的是透過希爾伯特空間理論，了解量子系統中量子糾錯碼的數學框架；以及避免在傳送時因相位失調及其他量子噪音而令量子資訊發生錯誤。

施博士透過研究各種數學技巧和工具以建立一些新的理論成果或改善現有的框架，例如改變量子態集之間的物理轉換方式，以及築構一些簡單有效的編碼和解碼量子電路，提升量子通道中的數據傳送效率。

雖然施博士認為他的研究以理論為主，在商業層面上的應用還有一大段距離，但無疑它能讓工程師有機會了解不同的現象，以及研發更優質的量子設備。其中最理想的實際用途就是建造比傳統數碼電腦更具效率的量子電腦，以透過執行量子計算法來解決更為複雜的問題。